1. Technical Field
The inventive concept relates to a method of manufacturing a phase change memory device and, more particularly, to a method of manufacturing a phase change memory device using a cross patterning technique.
2. Related Art
So as to improve the integration degree of semiconductor devices, fine patterns should be indispensably fabricated. That is, so as to integrate many elements in the defined area, individual elements should be scaled down. Miniaturization to line widths and spaces of the patterns should be preceded in order to reduce the sizes of the individual elements. Currently, it requires a line width below the resolution of the photolithographic light source in semiconductor devices, especially memory devices, so that it is difficult to form fine patterns.
Various methods of fabricating fine patterns have been researched and the cross patterning technique as a part of fine pattern formation method is suggested. A cross patterning technique is a method for fabricating patterns of fine line widths at intersections by carrying out a double patterning process in the form of orthogonal lines.
Currently, the diodes of the phase change memory device are fabricated by using the crossing patterning technique. That is, in the prior art, a metal layer for a word line, a barrier metal layer and a polysilicon layer are stacked and then double patterned by the cross patterning method to fabricate word lines and vertical diodes.
However, when the word lines are fabricated by the prior method, the polysilicon layer, the barrier metal layer and the metal layer for a word line having constant thicknesses are etched at a time so that the etching is heavily burdened, making it difficult to fabricate perfect patterns.